Method for liquid treatment of textile material

ABSTRACT

The bleaching or dyeing of textile material wherein the material is impregnated with treating liquor at a temperature below 100* C. and thereafter sealed within a container pressurized to the vapor pressure of the liquor at a higher temperature and then heating the liquor to the higher temperature.

United States Patent [1 1 Karrer et al.

[ Nov. 13, 1973 METHOD FOR LIQUID TREATMENT OF TEXTILE MATERIAL Inventors: Friedrich Wilhelm Johann Karrer,

Stockholm, Sweden; Alberto Pedretti, Rome, Italy Karrer System AG, Zurich, Switzerland Filed: Aug. 2, 1972 Appl. No.: 277,170

Assignee:

SZGY

[56] References Cited UNITED STATES PATENTS 2,936,212 5/1960 Karrer 8/157 X 3,528,180 9/1970 Karrer et al. 8/l49.l X

Primary Examiner-William 1. Price Att0meyJohn F. Learman et al.

[57] ABSTRACT The bleaching or dyeing of textile material wherein the material is impregnated with treating liquor at a temperature below 100 C. and thereafter sealed within a container pressurized to the vapor pressure of the liquor at a higher temperature and then heating the liquor to the higher temperature.

6 Claims, 1 Drawing Figure 50a 58a v 50 V 21 x 58 l} 1 MI NHL METHOD FOR LIQUID TREATMENT OF TEXTILE MATERIAL The invention relates to a method and apparatus for a liquid treatment of, fibrous, filiform or sheet textile material at a temperature above 100C.

The liquid treatment may for example be a bleaching or dyeing operation; the textile material may for example be yarn or piece goods in the wound state.

In a known method for treating fibrous or filiform material (for example for bleaching cellulose material in the absence of oxidation agents) as is described for example in Swedish patent 223,297, the operation is carried out at temperatures above 100C, for example at 125 to 130C. This can be achieved in that the material impregnated with treating liquid is treated with steam at a suitable temperature. However, steam can condense in the material and thus change the chemical concentration. This ha s'been found disadvantageous because the result of 'the treatment is generally dependent on maintaining a certain concentration of chemicals. On the other hand, if the heating is effected by hot air a considerable part of the treating liquid evaporates, changing the concentration in the opposite direction.

The invention is therefore based on the problem of developing a method and apparatus of the type mentioned at the beginning by which a temperature increase occurs in the material impregnated with liquid treating agents without steam condensing in the material or any evaporation taking place; the concentration of the treating liquid contained in the material is to remain unchanged.

According to the invention this problem is solved substantially in that the material is impregnated with treating liquor at a temperature below 100C and that thereafter the impregnated material is subjected in a sealed container to a pressure correspondingto the vapour pressure of the intended temperature and on passage of a heating medium, in particular steam, hot air or a mixture of air and steam, is brought in the corresponding pressure region to the desired temperature.

In the method according to the invention the material impregnated with treating liquid is first subjected in the sealed container to an increased pressure (corres ponding to the vapour pressure at the intended temperature) and the temperature is thereafter raised to the'desired degree. For this purpose, a heating medium such as steam, hot air or a mixture of steam and hot air flows through the container and thus through the material. In this manner the temperature can be increased without changing the concentration of the treating liquid.

Particularly suitable for carrying out the method according to the invention is an apparatus whose container containing the material to be treated is connected to a vacuum pump or to a compressor so that the container can be selectively subjected to a reduced or increased pressure (via suitable valve means).

According to the invention such an apparatus is equipped with a conduit by which the pressure side of the vacuum pump can be connected via a heat exchanger to the treatment container so that the compressed air is heated to the necessary'temperature.

The invention will be described hereinafter with the aid of the drawing. The latter shows an apparatus for carrying out the method according to the invention.

The apparatus includes a treatment container 21 which serves to receive the material to be treated. Yarn packages, rolls of fabric or loose material in the packed state are disposed so that the liquid or gas (i.e. the treating agent) flows through the material. By means of a pump 52 the container is evacuated via a conduit 30, a conduit 59, a valve 60 (when open) and a conduit 55. A four-way valve 51 is provided which in the position illustrated in the drawings connects the suction side of the pump52 to the conduit 59 whereas the pressure side is connected via a conduit 53 to an outlet 56. After evacuation of the container and closing the valve 60 the treating liquid is introduced through the conduit 30 (after opening a valve 31) from a source which is not shown in detail in order to impregnate the material. The treating liquid may be at a temperature of 20 to 30C.

The supply of the treating liquid and the impregnation may of course also be effected by evacuating via a conduit 48 and a conduit 55 while gradually supplying treating liquid uniformly through the conduit 30 to the container and thus to the material.

Excess liquid is removed by evacuation or discharging with the help of the vacuum pump 52. Hereafter compressed air is supplied by the pump via the conduit 48, whereupon the valve 49 is opened and the four-way valve 51 switched so that the pressure side of the pump is connected to the last-mentioned conduit 48.

The air may be supplied for the heating completely or partially through a heat exchanger or air heater 57 and a conduit 50. In this manner the pressure reaches the corresponding vapour pressure at the temperature at which the treatment is to be carried out, for example 2.8 atm for a temperature of 130C.

Instead of increasing the pressure by means of compressed air (as described above) steam may be supplied under the necessary pressure from a source which is not shown in detail via a conduit 58 including a valve 58a, or a mixture of compressed air and steam may be supplied.

When the pressure has reached the desired value in the manner indicated to further heat the material hot air may be introduced by bringing the pressure side of the vacuum pump 52 via the conduit 52b including'the valve 52a into connection with the conduit 50 and the valve 50a provided thereon, the air being heated to the necessary temperature prior to entry into the container in the air heater 57. Simultaneously, the valve 31 of the conduit 30 is opened so that the heating medium flows through the material disposed in the container.

As heating medium, instead of air steam may be supplied through the line 58; the air need not then be heated but can if desired be supplied cold through the conduit 48. In this case a water separator should be in- I corporated or the steam-air mixture introduced tangentially so that the condensate deposition takes place in the container.

We claim:

l. A method of treating fibrous, filiform or sheet textile material at a temperature above 100C. comprising impregnating said material with a treating fluid at a tain said material, a vacuum pump in communication with said container for selectively evacuating or pressurizing said container, a heat exchanger, and means establishing communication between the pressure side of said vacuum pump and said container via said heat exchanger. 

2. The method according to claim 1 wherein said heating is effected by steam.
 3. The method according to claim 1 wherein said heating is effected by hot air.
 4. The method according to claim 1 wherein said heating is effected by a mixture of steam and air.
 5. The method according to claim 1 wherein said material is maintained in a container during the impreg-nation, pressurization, and heatiNg thereof.
 6. Apparatus for carrying out the method according to claim 1 characterized by a container adapted to contain said material, a vacuum pump in communication with said container for selectively evacuating or pressurizing said container, a heat exchanger, and means establishing communication between the pressure side of said vacuum pump and said container via said heat exchanger. 